<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <!--区域-->
    <div id="app">
        <p>用户名是： {{ username }} </p>
        <input type="text" v-model='username'>
        <hr>
        <input type="text" :value='username'>
        <hr>

        <select name="" id="" v-model='city'>
            <option value="">请选择城市</option>
            <option value="1">北京</option>
            <option value="2">上海</option>
            <option value="3">广州</option>
            <option value="4">深圳</option>

        </select>
    </div>

    <!--引入-->
    <script src="./lib/vue-2.6.12.js"></script>

    <!--创建实例对象-->
    <script>
        const vm = new Vue({
            el: '#app',
            data: {
                username: 'zhangsan',
                city: ''
            }
        })
    </script>
</body>
</html>